BMW F13 Caliper Rebuild Kits

Brake caliper piston seals are there to maintain brake system pressure and prevent fluid from leaking out from inside the caliper. When a seal goes bad or becomes damaged the brakes lose pressure, leading to a soft brake pedal, sticking caliper, or even a total loss of your brakes. Brake calipers also need periodic rebuilds because the inner piston can seize from rust. With a piston stuck in the retracted position, the brakes are no longer functioning on that wheel. If the caliper is stuck in the extended position it's putting clamping force on your brakes - dragging the brakes, front wheel vibrations, pulling to one side, excessive brake dust and heat, and potentially even a brake pad fire. For cars that see significant track use, regular caliper rebuilds are essential because higher temps lead to rubber seal failures sooner.

Rebuilding your calipers should be part of a regular brake overhaul. The calipers must be removed from the car and disassembled. It's not a particularly difficult job to do but is messy and takes some expertise so that you don't ruin the piston or new seals. Rebuilding calipers is more cost effective than buying replacement calipers. However you service the calipers don't prolong their maintenance until it's too late!

This caliper bushing kit will eliminate flex caused by weak rubber caliper bushings. As the brake pedal is pressed the caliper grabs the rotor and twists on its mounting bushings. The rubber bushings allow the caliper to deflect and twist which affects pedal feel and results in uneven pad wear. These solid brass bushings will not twist or deflect so your calipers can squeeze the pads evenly on both sides of the rotor (sort of like what multi-piston big brakes do). This will give you much longer pad life and a more consistent pedal feel. This is the most complete kit we have ever sold with stainless steel caliper slide bolts, o-rings, and new dust boots. Unlike other kits, these bushings are pressed into the caliper and will not shift or slide on their own.

Installation is straightforward: remove the old rubber bushings and press in the new brass bushings (we recommend special tool 003326ECS03). High temp caliper grease or anti-seize is required. The new bushings include an inner o-ring that helps trap grease on the slide bolt, reducing friction and wear.

Stoptech Big Brake calipers are designed to be serviced and rebuilt just like any factory caliper. The pistons will probably last the life of the car but the seals can become brittle from extreme heat or extreme cold. Sometimes they just get damaged from debris. For racing environments it's best to rebuild the calipers often (maybe even several times a year). At least you should always have spare caliper seals on hand.

These are the genuine Stoptech caliper seals (dust boots and pressure seals). We sell these to service a PAIR of pistons (1 boot and 1 seal per piston). You will need to measure your existing pistons or seals to order the correct rebuild kits. Sorry, there are too many variables to tell you which pistons you have with only your car info. It's easy to measure and you don't have to remove the pistons from the calipers. Stoptech pistons are metric sized and in 2mm increments. Use the chart below to match your measurments to a rebuild kit.

There are a few ways to determine which caliper seals you need. You can measure from the overall outside diameter of the dust boot (A); the inside diameter of the piston (B); or the outside diameter of the piston body (not the tip protruding from the seal!) (C). If measuring the piston body the whole piston has to come out of the caliper housing. Just measuring the tip will give a false measurement. Remember to measure each of your pistons as piston sizes can vary even within the same caliper. Click the image at left for a larger version.

We sell rebuild kits for a PAIR of pistons - 1 seal and 1 boot per piston. For example -For a 4-piston caliper you only need to order 2 rebuild kits.For a 6-piston caliper you only need to order 3 rebuild kits.But make sure you measure each piston!

These rebuild kits fit with StopTech caliper pistons only. Sorry, returns are not accepted for opened piston seal kits.

Installs bushings straight and true with minimal effort. Includes tools for both iron and aluminum calipers. Purchase only one tool set for your entire caliper guide bushing upgrade - tools are not one time use.

This kit will eliminate caliper twisting caused by rubber guide pin bushings. This kit, consisting of precision guide pins and machined brass guide bushings will allow your calipers to squeeze evenly on both sides of the brake rotor, just like expensive multi-piston big brake kits. This will result in much longer pad life and more consistent brake system feel. These are a must if you race your BMW. This kit is SCCA and BMW CCA Club Racing approved. This kit fits both the front or rear calipers (but sold per axle). The ideal set-up is to run both front and rear on your car. Installation is quite simple. Does not fit E30 318/325 with Girling calipers nor E24 M6/E28 M5.